To address the National Institute on Aging?s strategic aim of understanding mechanisms underlying the pathogenesis of AD, related dementias, and neurodegenerative disorders of aging (Goal D-2), we propose an extension to Project 1 of the currently funded Center for the Study of Aphasia Recovery (C-STAR; P50 DC014664, referred to here as POLAR) to investigate further neurological and health-related factors that predict cognitive-linguistic decline in stroke survivors. Aphasia, a language impairment caused by damage to the brain's language regions, persists chronically in approximately 30% of stroke survivors. POLAR is a treatment study that aims to identify neuroanatomical, behavioral, genetic, and demographic predictors of treated aphasia recovery in individuals with chronic left hemisphere stroke. Preliminary analyses have shown that not all individuals improve, and recent evidence suggests that approximately one-quarter of individuals with post-stroke aphasia experience cognitive-linguistic decline over time. The purpose of this project is to extend the follow-up window for the POLAR study, to one-year post aphasia treatment. There is evidence to suggest that declining performance in stroke-induced aphasia is attributed to pathologic changes in the brain's white matter, referred to as leukoaraiosis. Leukoaraiosis is common in stroke survivors, and is often attributed to age, as well as cardiovascular health and other health concerns. In the general population, it has been associated with cognitive decline and loss of functional ability. By extending follow-up interval for the POLAR study, this study will address a new aim of evaluating the progression of leukoaraiosis and how it affects overall cognitive-linguistic ability in stroke survivors. To this end, participants will undergo the same speech/language and cognitive testing administered at study baseline. Participants will also undergo the same magnetic resonance imaging (MRI) protocol as at baseline (see the attached POLAR Research Strategy). The extent of behavioral change will be evaluated and related to neuroanatomical changes. The role of cognitive reserve and other personal factors in mediating the effects of leukoaraiosis will also be explored. The world?s population is aging, and with this trend, the global burden of stroke and dementia is also increasing. The study of leukoaraiosis in post-stroke aphasia is critical for identifying factors that may indicate cognitive-linguistic decline in stroke survivors, as doing so will also inform efforts to improve the evaluation of individuals at risk for developing cognitive impairment, AD, and other dementias (NIA Strategic Goal D-3). The world?s population is aging, and by 2050, it is expected that 17% of the world?s population (i.e., 1.6 billion people) will be over the age of 65 (1). Along with this increase in older individuals, the global burden of stroke (2) and dementia (3) is also increasing. The coming decades are expected to see a significant growth in the number of individuals living longer with post-stroke sequelae, attributed to the decline in stroke mortality rates (2, 4) and an increase in stroke rates in younger individuals (e.g., 20-44 years old (5); 45-64 years old (6)). In parallel, as individuals age, the prevalence of Alzheimer?s disease (AD) and other dementias continues to increase (3). This epidemiological trend means that aging research must consider the effects of stroke on the aging brain ? and likewise ? stroke research must consider how processes associated with aging affect long term outcomes. In essence, stroke survivors are aging, and aging research must consider this population, especially considering that by 2030, the number of stroke survivors could reach 70 million people worldwide (2). Accordingly, to address the National Institute on Aging?s strategic aim of understanding mechanisms underlying the pathogenesis of AD, related dementias, and neurodegenerative disorders of aging (Goal D-2), we propose an extension to Project 1 of the currently funded Center for the Study of Aphasia Recovery (CSTAR; P50 DC014664, referred to here as POLAR) to investigate further neurological and health-related factors that predict cognitive-linguistic decline in stroke survivors.